package main

import (
	"fmt"
	"io/ioutil"
	"os"
	"strings"
)

func main() {
	counts := make(map[string]int)
	for _, filename := range os.Args[1:]{
		data ,err:=ioutil.ReadFile(filename)
		if err !=nil {
			fmt.Fprintf(os.Stderr, "dup3: %v\n",err)
			continue
		}
		for _, line :=range strings.Split(string(data), "\n"){
			counts[line]++
		}
	}

	for line, n :=range counts{
		if n>1{
			fmt.Printf("%d\t%s\n", n,line)
		}
	}

}